Contrast color for Planner cards on the board
To make each card distinct and easy to read, the color of the card/task should be contrasting to the background color. Themes should have options to change the background colors.
Cards can also have colors like the options in Sticky notes, where you can change the color of sticky.
Christopher R Souser commented
Agree this is important for them to work like the color coding of sticky notes on normal Agile boards but it is also an Visual Accessibility and ease of use item that is pretty important.. otherwise all of the white boards will small color labels just all kind of blend into each other.